engleski

Changes in activity of antioxidative enzyme glucose-6-phosphate dehydrogenase induced by Fe2+ and Fe3+ in carp liver.

Iron is an essential element but it can also be toxic. The presence of even the smallest quantities of free iron in the cell leads to the generation of a wide range of free radicals which can react with a wide spectrum of cell components (DNA, proteins, lipids) and cause serious cellular damage. The aim of this study was to monitor by histochemical and morphometrical methods (Lucia G 4.8) the effects of the two oxidation states of iron on the activity of antioxidative enzyme glucose-6-phosphate dehydrogenase (G6PDH) in carp (Cyprinus carpio L.) liver under conditions of chronic exposure to maximum allowed waterborne iron concentrations. The activity of the enzyme lactate dehydrogenase (LDH), marker for cell/tissue damage was also monitored. Carp were held for 70 days in aquaria with constant iron concentration (1 mg/L). Liver tissue samples of control and exposed animals were taken every day during the first four days of the treatment, thereafter in intervals of two or seven days until the final 70th day of the treatment. Both forms of iron produced nearly total inhibition of the activities of G6PDH. Activities were reduced in time-dependent manner. Diffuse LDH activity increased more in treatment with Fe (III) which showed that Fe (III) was more toxic. These results indicate that the maximum allowed waterborne iron concentration during the prolonged treatment is sufficiently high to induce the significant reduction of the activity of G6PDH, one of the most important antioxidant enzymes in cell.

glucose-6-phosphate dehydrogenase; liver; carp; iron

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